Electrically-repeating signal



(No Model.) 2 Shets-Sheet. 1-.

s. 13. FIELD. ELEOTRIGALLY REPBATING SIGNAL. No. 488,550. PatentdIDec'. '27, 1892.

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2 sheets shetz.

(No Model.)

S. D. FIELD. BLBUTRICALLY REPEATING. SIGNAL.

Patented Dec. 27,1892.

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NITED STATES PATENT OFFICE.

STEPHEN DUDLEY FIELD, OF YONKERS, NEW YORK.

E LECTRICALLY-REPEATING SIGNAL.

SPECIFICATION forming part of Letters Patent No. 488,550, dated December 27, 1892.

Application filed March 5, 1892. Serial No. 23,866. (No model.)

To all whom it may concern:

Be it known that I, STEPHEN DUDLEY FIELD, a citizen of the United States, residing at Yonkers, in the county of Westchester and State of New York, have invented certain new and useful Improvements in Electrically-Repeating Signals; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The object of this invention is to relay electrical vibrations or undulations from one circuit to another and also to increase the distance at which intelligible inter-communica tion may be held.

In carrying out my invention I provide at the intermediate or relay station means for creating in the several lines emanating therefrom electrical vibrations or undulations of great rapidity, the several circuits being connected in inductive relation, and provide at the terminal stations means for setting up counter vibrations or undulations which react at the relay station upon apparatus 10- cated there and transfer with increased effect the vibrations or undulations to another line.

The essential feature of the invention con sists in originating vibrations at a central point and establishing communication between several distant points by damping at one such distant point the vibrations developed at the central point and causing by such damping action an intensified reproduction of the vibrations at another distant point.

The invention also involves improvements inapparatus for carrying out this method of operation, the several features of novelty of which will be hereinafter described in the specification and definitely indicated in the appended claims.

In the drawings which illustrate the invention, Figure 1 shows diagrammatically the apparatus arranged at a relay station; Figs. 2 and 3 are detail views of parts of apparatus illustrated in Fig. 1; Fig. 4 shows a modification of the system illustrated in Fig. l, the dynamo electric machine utilized in theformer system being omitted; Fig. 5 shows a modification of the vibration producing mechanism at the relay station; Figs. 6, 7 and 8 are details thereof.

Referring first to Fig. 1, A represents a diaphragm mounted upon a suitable box preferably of metal but insulated therefrom; Through the top of the box extends a tube B mounted air-tight in the box by means of an elastic washer O, a nut D and co operating j am nut permitting the joint to be made airrtight.

Connected with the tube B is a pump or other suitable device E for exhausting the air from the chamber formed by the diaphragm and box. The mouth of the tube B enters the box and stands in close relation to the face of the diaphragm or preferably to a contact plate F of inoxidizable conducting material, such as an alloy of platinum and iridium. On the upper side of the hollow box is a cup G provided with a stop cock by which air may be admitted to the box. The cup is filled with sponge, cotton waste, or some other suitable porous material for filtering the air which enters the box. Bymeans of the stop cook a slow admission of air may be permitted.

Confronting the diaphragm is a magnetizable core preferably a polarized magnet provided with a coil H, the terminals of which are connected to the line over which communication is desired to be established. The diaphragm should of course be of proper material at least at the portion which confronts the magnet to be capable of inductive action thereon. The tube B should be of metal, or, if not of such material, provision should be made for establishing electric communication with the contact point.

The diaphragm and frame of the box form the terminals of a local circuit I which includes the primary coil of an inductive apparatus, a secondary coil of which is connected with a switch J and with the several communicating lines in multiple arc. The preferred form of inductive apparatus is a shunt wound dynamo electric machine, several forms of which were described in my application Serial No. 417,249, filed January 7, 1892. In the form shown the armature is provided with two windings, one for low and the other for high voltage. is connected with the local circuit I and the other to the switch J and earth or a return conductor. The field-magnet shunt is preferably connected with the brushes through which the line currents are led. With this The low Voltage winding tory electric action.

construction, when a partial vacuum is produced in the box the diaphragm will be forced inwardly by air pressure and will stop the opening of the tube B, which will remain in this condition until sufficient airleaks through the stop cock, when the diaphragm will withdraw by its own resiliency. A further exhaustion will then occur and the opening in the tube B will again be closed. This cycle of operations occurs with extreme rapidity. With each opening and closing of the contacts formed at the mouth of the tube B, the resistance of the local circuit I is changed and the dynamo is thrown from a condition of no'load' to full load; thus electrical vibrations or undulations are thrown upon the lines, of such extreme rapidity as to be above the recording ability of electro-magnetic apparatus. It will be noted that these vibrations are forced upon the lines by an independent generator and that the two lines duringa signaling operation will be in a state of continuous electrical vibration, and the reinforcement of the transmitting impulses is accomplished by an interference at the repeating station with these forced vibrations. The dynamo is so wound that the circuit I will carry a current of low voltage preferably about one volt. Between the sides of this circuit is placed a condenser K by which the sparking at the contact point F may be reduced.

(Jo-operating with the switch .I are a series of contacts by which more or less of the coils H may be given to the several lines. The mode of accomplishing this is clearly indicated in Fig. 2, where the ends of the coils are supposed to be connected to line and the several contacts communicate with intermediatepoints thereof. Forlines of equal length the switch would be put upon the middle contact and by shifting it either way difference of line resistance may be compensated. Since the current proceeding from the high tension coil of the generator passes around the two portions of the coil H in opposite directions the magnet will be in a state of equilibrium so far as these currents are concerned, but both lines will be in a state of intense vibra- The distant ends of the lines may be provided with ordinary signaling apparatus... For telephonic communication the usual transmitting apparatus may be employed as indicated in Fig. 5. nals are thrown upon line from the distant stations a disturbance of the balance of the two circuits occurs at the intermediate station and the normal vibration of the diaphragm A is interfered with, and this, combined with the reaction between the two sections of the coil H, throws intensified vibrations upon the other line. The rate of vibration of the diaphragm may be governed by the amount of air permitted to enter through the stop cock. In this way vibrations may be repeated from one circuit into another with great rapidity and a very slight fluctuation at a terminal station may be made to produce will in some cases yield good results.

When siga very considerable change at the intermediate station.

In Figs. at and 5 are shown an organization in which the dynamo is dispensed with which In this case the two lines after passing differentially through the coil H are connected with earth. In order to understand the method of raising the tension exercised in this structure, let us imagine the operation of an ordinary induction coil having two secondary coils. If both secondaries are open equal potentials will appear at the terminals of each, but if one secondary coil be closed on itself, the potential of the remaining coil will be very much reduced, or if the resistance of one coil be I varied current will be varied in the other coil; also, if an opposing elcctro-motive-force be sent through one coil, an increase of current will be developed in the other coil. A similar state of affairs exists in my apparatus. The two circuits on the polarized magnet correspond to the two secondary coils instanced. Induced currents set up in the two windings by the vibration of the diaphragm create rapid electrical vibrations on the two lines, and when opposing or assisting vibrations or undulations are transmitted over one line from the distant terminal they are repeated with increased eflect upon the other line.

In the arrangement shown in Fig. 4 the magnetic field should be made as intense as possible, which may be effected by using a multipolar magnet as shown, and the end of the tube B may with advantage be provided with a rubber washer as indicated at W. The vibrations or undulations might be repeated into more than one circuit by winding the several circuits into which repeating is to be effected about the coil H in differential relation to the main line. In lieu of the differential winding the coil H may be arranged in a Wheatstone bridge, to the sides of which the two lines are connected. So long as the currents on both lines are equal the bridge coil will be neutral, but when any variation in either line occurs the coil will become active. It is deemed necessary only to mention this, as the bridge system and differential winding are now synonomous in the art.

In Figs. 5, 6 and 7 are shown another method of maintaining the vibration of the diaphragm. In this case the tube or nozzle B is connected with the air pump, and connected with the diaphragm is a light plunger L preferably provided with one or more perforations as indicated in Fig. 8, said plunger normally occupying the position indicated in the figures; when, however, the air in front of it is exhausted apartial vacuum is created in the box and an external air pressure forces in the diaphragm, admitting air through a channel M, when the diaphragm springs back and a further exhaustion takes place. The stem of the plunger is mounted adj ustably on the diaphragm so that it may be set to a position of delicacy. Such a mode of adjustment is indicated in Fig. 7. The plunger should be made as lightas possible and to this end may be formed of aluminium.

Increased ease of movement may be effected by inclosing both sides of the diaphragm and establishing a small communicating opening from one side of the diaphragm to the other so that the air on both sides of the diaphragm will be greatly rarefied as shown in Fig. 5, thus relieving the diaphragm of the impedence due to air resistance which at high speeds of vibration becomes a factor of considerable resistance. A small leak opening controlled by a stop cock is provided for the lower chamber. 4

I do not wish to be confined to any specific type of dynamo electric machine, it being obvious that a unipolar, bipolar or multipolar machine are equally well adapted to the combination shown, the only requisite being that the commutators shall be of a character which will be practically noiseless in operation.

The instrument described as a relay may be employed with advantage at a terminal station. In this case the switch J will be thrown so that but few convolutions will be on the home circuit.

When the instrument is referred to as a relay in this specification it is to be understood that its use as ahome instrument is included. In such a case the relay and one terminal station are at the same point.

Having 'thusdescribed my invention what I claim as new and desire to secure by Letters Patent is:-

1. In a system for repeating electrical vibrations or undulations the combination of two or more lines inductively related at a relay station, means for producing forced electrical vibrations or undulations in the lines at such station, and means for varying the force of such undulations 0r vibrations at the distant end of either line. b

2. A system for repeating electrical vibrations from one circuit to another comprising two circuits inductively related, a generator air therefrom, the diaphragm being adapted to close the mouth of the tube after partial exhaustion, and means for admitting air into the receptacle, whereby a rapid vibratory action of the diaphragm may be produced.

5. The combination of a diaphragm provided with means for maintaining it in rapid forced vibration, a local circuit controlled by the diaphragm, and an induction device having its primary circuit connected with the local circuit, and its secondary circuit connected to two lines leading to different stations.

6. A relay station for electrical vibrations or undulations having the line terminals at the relay station connected with coils inductively related, means for graduating the relative inductive effect of the lines, means for transmitting to the lines at the relay station rapid forced vibrations or undulations, and means at the distant station for varying the intensity of such vibrations or undulations in either line.

7. A system for repeating electrical vibrations or undulations from one line to another, comprising a rapidly vibrating diaphragm, a magnet inductively related thereto a coil or coils around said magnet, said coil or coils being differentially connected to the two lines.

In testimony whereof I affix my signature in presence of two witnesses.

STEPHEN DUDLEY FIELD.

Witnesses:

RYOBT. H. READ, VIoToR E. BURKE. 

